t 68 6 ] 
Grenades, Obfervations on the climate of the, p. i\6. Rain fallen there from June 
1772, to June 1773, p. 217. 
Gunpowder. Its force generally attributed to the fudden extrication of a great quantity 
of permanent aerial fluid, v/ithin a narrow fpace incapable of containing it, p. 391. 
This elaftic fluid fuppofed by Robins to contain 250 times the bulk of the powder, 
ibid. Opinion of Count Saluce on this fubjedt, p. 392. Ufes to which the extri- 
cation of fo much permanent aerial fluid has been put by philofophers, p. 392. 
Account of abrafs air gun, contrived by Mr. Maty of Turin, ibid. And of one by 
Mr. Antoni, p. 393. What the difference between the quantity of e'aftic fluid ob- 
tained by Robins, and others, may have been owing to, p. 393. Bernoulli’s cal- 
culation of it probably neareft the truth, but proves the jullnefs of that of the 
others, p. 394, 393. Nature of gunpowder explained in a different way from what 
it has hitherto been, p. 395 — 397. Nitre and charcoal fufhcient of them- 
felves to make very good, p. 397. Its force owing to the extrication of the de- 
phlogifticated air from the nitre, and of the inflammable air from the charcoal, by 
the fire which inflames it, p. 398. Difference of the inflammation of gunpowder, 
and of dephlogifticated and inflammable air in the air-piflol, what owing to, ibid. 
Probable that the dephlogiflicated and inflammable air, extricated in the firing of 
it, undergoes a diminution by its inflammation, p. 401. Agreement of this fuppo- 
fltion with the analyfls of gunpowder, as made by Abbe Fontana, p. 402. Accu- 
rate calculation of the expanfion of, a very difficult undertaking, p. 403. Reafon 
why it does not want a free accefs of common air to be confumed by fire, p. 404. 
Why a Angle fpark of fire propagates the combuftion throughout it with great rapidity, 
p. 405. Reafons for thinking modern philofophers would have difcovered it, p. 406. 
Gypfum . More vitriolic acid in gypfum than in felenitical fpars, p. 17. How diftin- 
guifhed from other fubflances of the fame appearance, p. 28. 
H. 
Harfz. Barometrical obfervations in the mines of the, 486 — 50 2. 
Hermaphrodites divided into two kinds, the natural and uncommon, p. 280. Account 
of the natural, p. 281, Of the unnatural, ibid. One part of each fex which they 
do not poffefs, p.281. Such hermaphrodites appear at firft view to be females, 
and are very frequent among horfes, p. 282. Defcription of one of this fort, p. 281. 
In general would apppear an object of chance, p. 284. Circumftance in the pro- 
duction of hermaphrodites in cattle, which feems to be an eftablifhed principle in 
the ceconomy of propagation of that fpecies of animal, and not a production of 
chance, p. 284. 
Horfe. Account of the difle&ion of an hermaphrodite, p ,282, 
4 
Hunter 
